It is proposed to continue studies of the cerebral metabolic and vascular effects of clinically used anesthetic agents and related drugs and techniques. Studies include measurements of systemic hemodynamics, cerebral blood flow, cerebral metabolic rates, and determination of cerebral tissue levels of phosphocreatine, ATP, ADP, AMP, lactate, pyruvate, glucose and glycogen. Changes in the above variables will also be correlated with EEG changes. Possible cerebral beneficial and/or detrimental effects will be looked for and tested in various stress animal models in whom regional or global ischemia will be induced prior to introducing the test anesthetic drug or technique. Impact of the test intervention will then be compared with controls. It is intended that these studies will help clarify the possible therapeutic roles of anesthesia in the management of head injury and stroke and will also help identify proper anesthetic selection in patients undergoing surgery for intracranial pathology. BIBLIOGRAPHIC REFERENCES: Stullken, E. H., Milde, J. H., Michenfelder, J. D., Tinker, J. H.: The Nonlinear Responses of Cerebral Metabolism to Low Concentrations of Halothane, Enflurane, Isoflurane, and Thiopental. Anesthesiology 46:28-34, January, 1977. Michenfelder, J. D. and Milde, J. H.: Failure of Prolonged Hypocapnia, Hypothermia, or Hypertension to Favorably Alter Acute Stroke in Primates. Stroke 8:87-91, January-February 1977.